Single and multiple acid extract antigens in Campylobacter serology.

Campylobacter IgA, IgM and IgG antibody titers of 442 patients with positive isolations of Campylobacter were tested in enzyme immunoassay (EIA). Of the patients, 330 showed elevated antibody end-point titers to a single acid extract antigen prepared from a C. jejuni strain. Sixteen further patients had fourfold or greater antibody titer changes in paired sera. Nine patients, who did not show elevated antibody titers for the single extract, had positive serological responses for a multiple acid extract prepared from six C. jejuni/coli and a C. fetus subsp. fetus strain. The specificity of the test, based on Campylobacter antibodies of 200 healthy blood donors, was 99%. The use of the single acid extract gave a sensitivity of 78%. The additional use of the multiple acid extract raised the sensitivity to 80%.